Simultaneous Determination of Cis- and Trans-palmitoleic Acid in Rat Serum by UPLC-MS/MS

Background: Cis -palmitoleic acid ( c POA) and trans -palmitoleic acid ( t POA) are isomers of palmitoleic acid, which are monounsaturated fatty acids, affecting glucose and lipid metabolism, and reducing insulin resistance. t POA was better than c POA in regulating lipid metabolism in hyperlipidemia mice, but the pharmacokinetic, metabolic transformation and structure-activity relationship have not been reported. Method: A precise and accurate ultra performance liquid chromatography-tandem mass spectroscopy (UPLC–MS/MS) method was developed to determine c POA and t POA simultaneously. c POA and t POA were administered i.g. (intragastric gavage) to rats at 75 mg/kg, serum samples were analyzed by UPLC-MS/MS on a reverse-phase BDS C18 column equilibrated and eluted with water (A) and acetonitrile (B) at a flow rate of 0.3 mL/min. Results: : The calibration curves for c POA and t POA were linear over the range 0.1~12 μg/mL. Analytes were monitored by selected-reaction monitoring in negative electrospray ionization mode. The Tmax of c POA was 0.94±0.44 h and the Cmax 8.17±1.97 μg/L, and the Tmax of t POA was 1.50±0.98 h and the Cmax 14.77±11.91 μg/L. AUC 0-24h of c POA and t POA were 59.45±29.83 and 113.88±72.25 mg/L*h. Conclusions: : The method was applied in pharmacokinetic study of c POA and t POA in rat serum successfully. Besides, it’s found the concentration of c POA and t POA fluctuated in serum of rats with the consistent trend, which may be reciprocal bio-convert in the body.